[LSC] Add LOCAL_LICENSE_KINDS to cts

Added SPDX-license-identifier-Apache-2.0 to:
  tests/signature/api-check/system-api/Android.mk

Bug: 68860345
Bug: 151177513
Bug: 151953481

Test: m all

Exempt-From-Owner-Approval: janitorial work
Change-Id: I3433316ca50fc877fbe9fc4d626503df8ad3b662
1 file changed